Composite brake drum



June 4, 1935.

D. J. CAMPBELL COMPOSITE BRAKE DRUM all',

Filgd NOV. 13, 1933 IMI-Uh Patented `lune 4, 1935` UNITED STATES ammi COMPOSITE BRAKE DRUM Donald J. Campbell, Spring Lake Township, t-

1 tawa. County, Mich.,

assignor to Campbell,

Wyant & Cannon Foundry Company, Muskogon, Mich., a corporation of Michigan Application November 1s. 193s, semi No. 691,311

4 Claims.

This method relates to a brake drum and also to its method of manufacture.

One object of the invention is to more easily and thoroughly join an iron of an alloyed composition braking band to a steel or other thin metal supporting shell than has been heretofore accomplished.

The invention consists in producing a supporting shell, heating the shell suiliciently to prevent chilling of molten copper, revolving the shell slowly in a suitable mechanism, depositing into the shell a measured quantity of molten iron that has been alloyed with copper, increasing the rate of rotation while the iron is 'in a molten state until a sufficient quantity of the copper is driven lto the inner peripheral surface of the shell and separates the molten iron from the shell by a thin layer of copper, the copper being joined to the shell and to the ironas by fusion.

The invention is carried out by the mechanism disclosed in the accompanying drawing, in which:

Fig. 1 is a sectional view of a mechanism for revolving the shell and depositing of the metal in the shell.

Fig. 2 is a sectional view of a brake drum produced by the invention.

While a mechanism is illustrated by themechanism of the drawing, it is understood that the invention is not confined to any distinct mechamsm.

Similar characters of reference refer to similar parts throughout the several views of the draw- 1ng.

Referring to Fig. 1, numeral I0 indicates a chuck housing which receives jaws II, such jaws being shown in contracted position but capable of being extended outwardly relative to the housing I0 whereupon they are expanded and release thebrake drum held therein. The chuck housing I0 is located in suitable bearings, one of which is indicated at I2, whereby it may be properly rotated.

Referring now particularly to Fig. 2, numeral I3 indicates a shell, preferably formed of sheet steel, having a cast iron liner I4 therein. A layer of copper or copper alloy I5 is positioned between the cast iron shell I4 and the vsteel supportin member I3.

In carrying out the invention lsit desirable to first melt the iron in a cupola, transfer it to an electric l furnace and introduce the desired quantity of copper and other alloys and where .the desired temperature for depositing into the revolving heated shell. It has been found that the quantity of copper may vary between 2 percent and 10 percent and in some cases even more, but for good results a. percentage of 4 percent. 'Ihe ltemperature in cupolas in which cast iron is melted for foundry purposes is seldom if ever below 2400 F. and with so-called hot blast furnaces may reach 2600 F. Therefore, to those skilled in foundry practice it is well known that cupola melted iron is at approximately 2400 to 2600 F. and that a transfer to an electric furnace would be to either elevate such temperature or maintain it as high as initially produced while the copper is melting and disseminating therethrough.

It will be appreciated that copper is of greater density than the cast iron and thus during the rotation of the shell, the molten copper will flow outwardly due to centrifugal force and contact against the inner side of the steel shell I3. Thus the copper will be positioned exteriorly of the cast iron braking drum. Also, copper is amuch better conductor of heat than cast iron and thus the outer oil shell will be more easily fused in its inner side.

There is produced a composite brake drum structure having an outer steel shell, an inner wearing band of cast iron through which part of the copper used may be disseminated and a layer or film of copper between the cast iron and steel. 'Ihere is an intimate and continuous joinder of the cast iron to the steel by means of the intermediate copper winch has all of the e'ects and characteristics of a complete and continuous brazing connection of the cast iron to the steel and by means of which fully as intimate a connection of the cast iron to` .the steel is made as if the cast iron was fused thereto. -At the same time the copper adds strength and toughness to the cast iron liner and also at the binding band between the cast iron and steel adds strength to the steel outer shell.

It is to be understood that my invention is not definitely limited to the metals herein recited as obviously each of these metals might be replaced by others having somewhat like characteristics.

The invention is defined in the appended claims.

I claim: g

1. The method of producing a brake drum which consists in providing a shell, melting a quantity of cast iron in a cupola. transferring it to an electric furnace and then introducing between 3% and 10% of copper thereto, rotating the shell, depositing the molten mixture within the shell while the shell is rotating and then cooling the mixture.

f the mass of iron and also being at least three percent thereof, and then rotating the shell at such a speed as to cause an appreciable separation of the metals due to the action of centrifugal force thereon and then cooling the several elements.

3. The method of manufacturing a brake drum which consists in providing a steel shell. rotating the shell, introducing molten copper and molten cast iron into the'shell eitherv before or after the start of its rotation, the rotation being of suflicient speed to cause partial segregation of the metals and then cooling the metals, vsaid copper content being between 3 and 10 percent.

4. The method oi' manufacturing brake drums which consists in providing a steel shell, rotating the steel shell, introducing into the steel shell while it is rotating, molten iron and copper, then rotating the said shell, iron and copper at a speed sumclent to cause separation of copper from the iron to form a film of copper between the steel shell and the iron.

DONALD J. CAMPBELL'M 

